Ampache is a web based audio/video streaming application and file manager. Versions prior to 4.4.1 allow unauthenticated access to Ampache using the subsonic API. To successfully make the attack you must use a username that is not part of the site to bypass the auth checks. For more details and workaround guidance see the referenced GitHub security advisory.
https://github.com/ampache/ampache/security/advisories/GHSA-p9pm-j95j-5mjf